O árbitro apitou depois do escanteio.

O is the masculine singular definite article, meaning the.

So o árbitro = the referee.

Portuguese uses definite articles very naturally before common nouns when referring to a specific person or thing. In this sentence, it is talking about a particular referee, not just any referee.

Árbitro is the standard word for a referee in sports.

A native speaker might also sometimes say juiz in sports contexts, especially informally, but árbitro is the more precise and standard term for the official in a match.

Also, note the accent:

• árbitro

The stress falls on the first syllable: AR-bi-tro.

Apitou is the pretérito perfeito (simple past / preterite) of the verb apitar.

It is:

• 3rd person singular
• from apitar = to whistle / to blow the whistle

So:

• eu apitei = I blew the whistle
• você/ele/ela apitou = you/he/she blew the whistle

This tense is used for a completed action in the past.

It can mean both, depending on context.

In everyday language, apitar can mean to whistle or to make a whistle sound. In sports, when the subject is the referee, it usually means to blow the whistle.

So in this sentence, o árbitro apitou is most naturally understood as:

• the referee blew the whistle

In other contexts, apitar can also mean to referee a game:

• Ele vai apitar o jogo. = He is going to referee the match.

Because de + o contracts to do.

Here is the breakdown:

• depois de = after
• o escanteio = the corner kick

So:

• depois de o escanteio → depois do escanteio

This kind of contraction is very common in Portuguese:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

Yes, when depois is followed by a noun phrase, it normally uses de.

Examples:

• depois do jogo = after the game
• depois da aula = after class
• depois do escanteio = after the corner kick

But if depois stands alone, it does not need anything after it:

• Eu falo com você depois. = I’ll talk to you later.

So:

• depois = later / afterward
• depois de + noun = after + noun

In Brazilian Portuguese, escanteio means corner kick or simply corner in soccer.

It is the standard Brazilian term used in football/soccer contexts.

A few useful examples:

• Foi escanteio. = It was a corner.
• Cobrar um escanteio = to take a corner kick

If you know European Portuguese, you may also see canto used there more often for corner kick.

Because Portuguese normally uses an article here: o escanteio.

That suggests a specific corner kick already known from the context of the game. English also usually wants an article in a full sentence like this:

• after the corner kick

So the Portuguese structure is very natural.

Yes, absolutely.

Both are natural:

• O árbitro apitou depois do escanteio.
• Depois do escanteio, o árbitro apitou.

The difference is mostly about emphasis:

• O árbitro apitou depois do escanteio. = neutral, starts with the subject
• Depois do escanteio, o árbitro apitou. = emphasizes the time sequence a bit more

Portuguese allows this kind of word-order flexibility quite easily.

A simple Brazilian Portuguese approximation:

• árbitro → AR-bi-tro
• apitou → a-pi-TOU
• escanteio → es-can-TEI-o

A few notes:

• árbitro has stress on the first syllable, which is why it has an accent mark.
• apitou has stress on the last syllable.
• In escanteio, the ei sounds like the ay in say.

Yes. In a soccer context, when a referee apita, it usually means he blew the whistle to signal something in the match.

The sentence itself does not say exactly why he blew it. It could be:

• to stop play
• to signal a foul
• to mark the end of a phase
• to indicate some decision

So apitou tells you the action, but not the exact reason unless more context is given.